US4884459A - Flow rate converter - Google Patents

Flow rate converter Download PDF

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Publication number
US4884459A
US4884459A US07/208,188 US20818888A US4884459A US 4884459 A US4884459 A US 4884459A US 20818888 A US20818888 A US 20818888A US 4884459 A US4884459 A US 4884459A
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US
United States
Prior art keywords
flow rate
rate converter
channels
tube
cylindric
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US07/208,188
Inventor
Yordan Y. Beyazov
Sasho G. Nenov
Vlayko S. Peychev
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
INSTITUTE PO TECHNICHESKA KIBERNETIKA I ROBOTIKA AN INSTITUTE OF BULGARIA
Institute po Technicheska Kibernetika i Robotika
Original Assignee
Institute po Technicheska Kibernetika i Robotika
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Institute po Technicheska Kibernetika i Robotika filed Critical Institute po Technicheska Kibernetika i Robotika
Assigned to INSTITUTE PO TECHNICHESKA KIBERNETIKA I ROBOTIKA, AN INSTITUTE OF BULGARIA reassignment INSTITUTE PO TECHNICHESKA KIBERNETIKA I ROBOTIKA, AN INSTITUTE OF BULGARIA ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: BEYAZOV, YORDAN Y., NENOV, SASHO G., PEYCHEV, VLAYKO S.
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/08—Detecting, measuring or recording devices for evaluating the respiratory organs
    • A61B5/087—Measuring breath flow
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
    • G01F1/34—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure
    • G01F1/36—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure the pressure or differential pressure being created by the use of flow constriction
    • G01F1/40—Details of construction of the flow constriction devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
    • G01F1/34—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure
    • G01F1/36—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure the pressure or differential pressure being created by the use of flow constriction
    • G01F1/40—Details of construction of the flow constriction devices
    • G01F1/42—Orifices or nozzles

Definitions

  • the invention relates to a flow rate converter used in medical technology and in particular in the diagnosis of lung diseases.
  • a known flow rate converter is disclosed in the catalog of the GOULD company (Netherlands).
  • the known device has a body with a cylindric tube disposed therein.
  • axial channels In the tube are disposed axial channels and its two ends are connected respectively with an incoming and an outgoing diffuser.
  • In the body In the body are machined inner circumferential conduits connecting the external row of axial channels with pipe connections disposed on the body to which is mounted a heating element.
  • There are some several thousand axial channels which occupy the whole section of the tube and they have an approximately triangular section. In order to carry out investigations in the entire range, a series of ten converters with different parameters and overall sizes is needed.
  • An object of the invention is to provide a converter of flow rate with a simpler manufacture technology and be able to avoid the need of having an entire set of converters.
  • a flow rate converter comprising a body with a cylindric tube formed therein.
  • longitudinally axial channels are disposed and its two ends are connected respectively with an inlet and an outlet diffuser.
  • a pair of inner annular conduits are machined connecting the external row of axial channels with pipe connections disposed on the body in which is mounted a heating element.
  • a replaceable cylindric body is disposed in the cylindric tube.
  • first axial channels On the circumferential surface of the cylindric body are formed first axial channels with a section providing for a laminar flow for which the Reynolds number is less than the critical.
  • second axial channels In the same cylindric body are disposed second axial channels of which at least one has cross-sectional area that is at least two times greater than the sum of the cross-sectional areas of the first axial channels and the flow in the second channels is turbulent.
  • Chamfers are formed in both ends of the second channels.
  • For each replaceable cylindric body corresponds a replaceable cover with openings that is fastened to the outlet diffuser.
  • Advantages of this invention include simplified manufacture technology and the ability to use just one converter with replaceable cylindric bodies instead of a set of converters with different over-all sizes.
  • FIG. 1 is a longitudinal axial section of the flow rate converter
  • FIG. 2 is a view similar to FIG. 1 of variant of the flow rate converter.
  • FIG. 3 is a section along A--A in FIG. 2.
  • the flow rate converter according to FIG. 1 comprises a body 1 in which is formed a cylindric tube 2 to the one end of which is fastened an inlet diffuser 3 with a nozzle 4.
  • the other end of the tube 2 is fastened to an outlet diffuser 5 on which is placed a replaceable cover 6 with openings 7.
  • two annular conduits 8 and 9 connected with two pipe connections respectively 10 and 11 which are disposed in the body 1. In the latter is inserted a heating element 12 closed by a cover 13.
  • a replaceable cylindric body 14 is mounted in the tube 2 and along the circumferential surface of the body 14 first axial channels 15 are formed (see also FIG. 3) with an equal rectangular cross-section.
  • a second axial channel 16 is perforated in the replaceable body 14 and has a round cross-section having (in this embodiment) a cross-sectional area about 10 times larger than the sum of the cross-sectional areas of the first axial channels 15. In both ends of channel 16 are formed chamfers 17.
  • the second axial channel 16 can have cylindric form or represent a combination of convergent and divergent parts with or without a cylindric part between them.
  • a handle 18 may be fastened to the body 1.
  • the body 1 and the tube 2 can represent and a single piece or can be separate pieces.
  • the number of the first axial channels 15 ensuring a laminar flow should be the same for each replaceable cylindric body 14 whereas the number and diameter of the second axial channels 16 is specific for each cylindric body 14 depending on the required measuring range. Compare FIGS. 1, 2, and 3. In these channels the flow is turbulent.
  • the total cross-sectional area of the openings 7 on each replaceable cover 6 is equal to or less than the cross-sectional area of the second axial channels 16 of the respective replaceable cylindric body 14.
  • the pipe connections 10, 11 can be connected in series with a pneumoelectric converter of differential pressure, an electronic circuit for tuning, a microprocessor system for processing of the obtained results or a recording device (not shown in the figures) in order to obtain final results from the investigation.
  • the converter operates in the following manner:
  • the flow entering through the nozzle 4 and diffuser 3 is separated into two flows.
  • the first flow is considerably smaller and passes through the first axial channels 15 which create a laminar flow whereas the second basic flow passes through the second axial channels 16 and is turbulent.

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  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Medical Informatics (AREA)
  • Surgery (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Biophysics (AREA)
  • Molecular Biology (AREA)
  • Pathology (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Pulmonology (AREA)
  • Physiology (AREA)
  • Measuring Volume Flow (AREA)
  • Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)

Abstract

A flow rate converter has a body with a cyclindric tube and an inlet and an outlet diffuser. The tube and body have inner annular conduits connecting with pipe connections disposed in the body. The body is also provided with a heating element. A replaceable cylindric body is inserted in the cylindric tube and is provided with first axial channels providing for a laminar flow and second axial channels of which at least one has a cross-sectional area at least two times larger than the cross-sectional area of the first channels. In both ends of the second channels are formed chambers while a replaceable cover with openings is fastened to the outlet diffuser.

Description

FIELD OF THE INVENTION
The invention relates to a flow rate converter used in medical technology and in particular in the diagnosis of lung diseases.
BACKGROUND OF THE INVENTION
A known flow rate converter is disclosed in the catalog of the GOULD company (Netherlands). The known device has a body with a cylindric tube disposed therein. In the tube are disposed axial channels and its two ends are connected respectively with an incoming and an outgoing diffuser. In the body are machined inner circumferential conduits connecting the external row of axial channels with pipe connections disposed on the body to which is mounted a heating element. There are some several thousand axial channels which occupy the whole section of the tube and they have an approximately triangular section. In order to carry out investigations in the entire range, a series of ten converters with different parameters and overall sizes is needed.
The disadvantages of this known converter include complicated manufacture technology and the requirement of having an entire set of separate converters with different over-all sizes in order to cover the complete range.
SUMMARY OF THE INVENTION
An object of the invention is to provide a converter of flow rate with a simpler manufacture technology and be able to avoid the need of having an entire set of converters.
This object is attained by a flow rate converter comprising a body with a cylindric tube formed therein. In the tube, longitudinally axial channels are disposed and its two ends are connected respectively with an inlet and an outlet diffuser. In the body, a pair of inner annular conduits are machined connecting the external row of axial channels with pipe connections disposed on the body in which is mounted a heating element.
According to this invention, a replaceable cylindric body is disposed in the cylindric tube. On the circumferential surface of the cylindric body are formed first axial channels with a section providing for a laminar flow for which the Reynolds number is less than the critical. In the same cylindric body are disposed second axial channels of which at least one has cross-sectional area that is at least two times greater than the sum of the cross-sectional areas of the first axial channels and the flow in the second channels is turbulent.
Chamfers are formed in both ends of the second channels. For each replaceable cylindric body corresponds a replaceable cover with openings that is fastened to the outlet diffuser.
Advantages of this invention include simplified manufacture technology and the ability to use just one converter with replaceable cylindric bodies instead of a set of converters with different over-all sizes.
BRIEF DESCRIPTION OF THE DRAWING
With these and other objects in view, which will become apparent in the following detailed description, the present invention, which is shown by example only, will be clearly understood in connection with the accompanying drawing, in which:
FIG. 1 is a longitudinal axial section of the flow rate converter;
FIG. 2 is a view similar to FIG. 1 of variant of the flow rate converter; and
FIG. 3 is a section along A--A in FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The flow rate converter according to FIG. 1 comprises a body 1 in which is formed a cylindric tube 2 to the one end of which is fastened an inlet diffuser 3 with a nozzle 4. The other end of the tube 2 is fastened to an outlet diffuser 5 on which is placed a replaceable cover 6 with openings 7. Along the inner surface of the tube 2 have been machined two annular conduits 8 and 9 connected with two pipe connections respectively 10 and 11 which are disposed in the body 1. In the latter is inserted a heating element 12 closed by a cover 13.
A replaceable cylindric body 14 is mounted in the tube 2 and along the circumferential surface of the body 14 first axial channels 15 are formed (see also FIG. 3) with an equal rectangular cross-section. A second axial channel 16 is perforated in the replaceable body 14 and has a round cross-section having (in this embodiment) a cross-sectional area about 10 times larger than the sum of the cross-sectional areas of the first axial channels 15. In both ends of channel 16 are formed chamfers 17.
The second axial channel 16 can have cylindric form or represent a combination of convergent and divergent parts with or without a cylindric part between them. A handle 18 may be fastened to the body 1. The body 1 and the tube 2 can represent and a single piece or can be separate pieces. The number of the first axial channels 15 ensuring a laminar flow should be the same for each replaceable cylindric body 14 whereas the number and diameter of the second axial channels 16 is specific for each cylindric body 14 depending on the required measuring range. Compare FIGS. 1, 2, and 3. In these channels the flow is turbulent.
The total cross-sectional area of the openings 7 on each replaceable cover 6 is equal to or less than the cross-sectional area of the second axial channels 16 of the respective replaceable cylindric body 14.
The pipe connections 10, 11 can be connected in series with a pneumoelectric converter of differential pressure, an electronic circuit for tuning, a microprocessor system for processing of the obtained results or a recording device (not shown in the figures) in order to obtain final results from the investigation.
The converter operates in the following manner:
The flow entering through the nozzle 4 and diffuser 3 is separated into two flows. The first flow is considerably smaller and passes through the first axial channels 15 which create a laminar flow whereas the second basic flow passes through the second axial channels 16 and is turbulent.
As a result of the laminar character of the flow through the first axial channels 15, the dependence between the generated pressure drop between the two pipe connections 10 and 11 and the flow rate is linear independently of the turbulent character of the flow through the second axial channels 16. The chamfers 17 augment considerably the flow rate coefficient. The replaceable cover 6 prevents any penetration of a back-flow that would cause errors in measuring.
Although the invention is described and illustrated with reference to a plurality of embodiments thereof, it is to be expressly understood that it is in no way limited to the disclosure of such preferred embodiments but is capable of numerous modifications within the scope of the appended claims.

Claims (5)

We claim:
1. A flow rate converter comprising
a body with a cylindric tube formed therein;
said tube being provided with inlet diffusing means at one end and outlet diffusing means at another end and a pair of spaced apart annular conduits;
said body being provided with a heating element and two pipe means communicating with said two annular conduits;
a replaceable cylindric body disposed in said tube, said replaceable body having a plurality of circumferential longitudinal axial channels communicating with said conduits;
said cylindric body also having a non-circumferential axial channel;
said non-circumferential channel having a cross-sectional area at least 2 times as large as the sum of the cross-sectional areas of said circumferential channels.
2. A flow rate converter as claimed in claim 1, further comprising
said circumferential channels having a cross section providing for a laminar flow with a Reynolds number smaller than the critical.
3. A flow rate converter as claimed in claim 1, further comprising:
said non-circumferential channel having chamfered ends.
4. A flow rate converter as claimed in claim 1, further comprising
a replaceable cover, said cover being provided with openings and being fastened to the outlet diffuser.
5. A flow rate converter as claimed in claim 1, further comprising
a plurality of non-circumferential channels.
US07/208,188 1987-06-16 1988-06-16 Flow rate converter Expired - Fee Related US4884459A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BG8780178A BG44992A1 (en) 1987-06-16 1987-06-16
BG80178 1987-06-16

Publications (1)

Publication Number Publication Date
US4884459A true US4884459A (en) 1989-12-05

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Family Applications (1)

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US07/208,188 Expired - Fee Related US4884459A (en) 1987-06-16 1988-06-16 Flow rate converter

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US (1) US4884459A (en)
EP (1) EP0295575A1 (en)
JP (1) JPH01145524A (en)
BG (1) BG44992A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999060343A1 (en) * 1998-05-04 1999-11-25 Medikro Oy Flow resistance of air flow flowtransducer
US7454984B1 (en) * 2007-08-31 2008-11-25 Delphi Technologies, Inc. Flow meter for measuring a flow rate of a flow of a fluid
US20100145212A1 (en) * 2008-11-17 2010-06-10 Laszlo Csatar Flow meter for pulmonary function tests

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2725123B1 (en) * 1994-09-30 1996-12-20 Soc D Thermoformage Et D Injec TIP EXPIRATORY FLOW MEASURING APPARATUS
DE4440161A1 (en) * 1994-11-10 1996-05-15 Mueller & Sebastiani Elek Gmbh Measuring head attachment
FR2766568B1 (en) * 1997-07-23 1999-09-10 Saime Sarl GAS FLOW SENSOR AND RESPIRATORY ASSISTANCE APPARATUS COMPRISING SUCH A SENSOR
FR2992845B1 (en) * 2012-07-05 2015-05-08 Isp System DEVICE FOR MEASURING A GAS FLOW FOR MEDICAL IMAGING

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1487989A (en) * 1922-04-18 1924-03-25 Leonard O Vose Apparatus for measuring the rate of flow of gases
US3220256A (en) * 1962-09-12 1965-11-30 Nat Instr Lab Inc Linear flow meter
US4418723A (en) * 1980-08-12 1983-12-06 Citizen Watch Co., Ltd. Flow restrictor
US4434976A (en) * 1981-12-11 1984-03-06 Nippon Steel Corporation Concentric multi-tube-system nozzle situated beneath the surface of the melt in a refining vessel

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4178919A (en) * 1978-04-03 1979-12-18 The Perkin-Elmer Corporation Flowmeter for providing synchronized flow data and respiratory gas samples to a medical mass spectrometer

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1487989A (en) * 1922-04-18 1924-03-25 Leonard O Vose Apparatus for measuring the rate of flow of gases
US3220256A (en) * 1962-09-12 1965-11-30 Nat Instr Lab Inc Linear flow meter
US4418723A (en) * 1980-08-12 1983-12-06 Citizen Watch Co., Ltd. Flow restrictor
US4434976A (en) * 1981-12-11 1984-03-06 Nippon Steel Corporation Concentric multi-tube-system nozzle situated beneath the surface of the melt in a refining vessel

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999060343A1 (en) * 1998-05-04 1999-11-25 Medikro Oy Flow resistance of air flow flowtransducer
US7454984B1 (en) * 2007-08-31 2008-11-25 Delphi Technologies, Inc. Flow meter for measuring a flow rate of a flow of a fluid
US20090056130A1 (en) * 2007-08-31 2009-03-05 Ross David A Flow meter for measuring a flow rate of a flow of a fluid
US20100145212A1 (en) * 2008-11-17 2010-06-10 Laszlo Csatar Flow meter for pulmonary function tests
US8585608B2 (en) * 2008-11-17 2013-11-19 Piston Kft. Flow meter for pulmonary function tests

Also Published As

Publication number Publication date
EP0295575A1 (en) 1988-12-21
BG44992A1 (en) 1989-03-15
JPH01145524A (en) 1989-06-07

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Owner name: INSTITUTE PO TECHNICHESKA KIBERNETIKA I ROBOTIKA,

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:BEYAZOV, YORDAN Y.;NENOV, SASHO G.;PEYCHEV, VLAYKO S.;REEL/FRAME:005016/0633

Effective date: 19880819

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FP Lapsed due to failure to pay maintenance fee

Effective date: 19931205

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362